Презентация к уроку геометрии на английском языке по теме Polyhedra

Polyhedra

Mikhаilichenko Yelena-Maths teacher

Tsoy Svetlana- English teacher

Polyhedron is a geometric body which consists of a finite number of intersecting planes

Prism is a polyhedron consisting of two parallel polygons, basing on finite numbers of rectangles which form a side surface.

V=SH

Pyramid is a geometric body which consists of some triangles with common vertex and the base.

V=1/3 SH

Cube is a prism with equal faces.

V= a³

,where a is an edge.

Regular Polyhedra

Non of the geometric body does not possess such beauty as regular polyhedra. There are 5 types of polyhedra: tetrahedron, cube, octahedron, dodehedron and icosahedron.

The Euler characteristic

The number of faces F

The number of vertices V

4

4

6

The number of edges E

8

Regular polyhedron

6

8

F+V-E=24

tetrahedron

12

6

12

20

cube

2

12

20

12

2

30

octahedron

dodecahedron

2

30

2

icosahedron

2

Regular Polyhedra in nature